Studies toward Antarctic Micrometeorite classification using abundant collection

我们研究了日本南极考察队JARE-37、38、39和41号收集的大量南极微陨石。JARE-37和38号的样本是从圆顶富士站的水箱中回收的，JARE-39号的样本是从大和陨石裸露冰原中回收的，JARE-41号的样本是从托图基裸露冰区回收的。特别是对含水蚀变矿物的研究取得了重要的成果。一般来说，大多数宇宙尘埃由含水改变的矿物质组成（超过50%）。另一方面，含水矿物组成的陨石仅限于碳质球粒陨石（~ 1%）。这种差异模式表明，太空中的含水矿物主要是宇宙尘埃，这是由于物质的脆弱物质造成的。研究发现，新近坠落的塔吉什湖陨石是一种新型的含水蚀变碳质球粒陨石，与南极微陨石有着密切的关系。在研究的第四年，我们总结了我们的研究成果，整理了我们发表的18篇论文，41篇摘要和300多页的《日本南极微陨石目录》。

We studied abundant Antarctic Micrometeorites collected by JARE-37, 38, 39 and 41, where JARE is Japanese Antarctic Research Expedition. Samples from JARE-37 and 38 were recovered from water tank for life in the Dome Fuji Station, those from JARE-39 from the Yamato meteorite bare icefield, and those from JARE-41 from the Tottuki bare ice area. Especially, important results were obtained from the study focused on the hydrously altered minerals. Generally, most of cosmic dust consists of hydrously altered minerals (more than 50%). On the other hand, meteorites consisting of hydrous minerals are limited to carbonaceous chondrites (〜1%). This mode of difference suggests that hydrous minerals in space fall as mostly cosmic dust, being ascribed from the fragile substance of the material. We found that recent fell Tagish Lake meteorite, which is a new type of hydrously altered carbonaceous chondrite, has a close relationship with the Antarctic micrometeorites.In the 4th year of our research period, we summarized our study and compiled our 18 published papers, list of 41 abstracts and catalog of Japanese Antarctic Micrometeorites with more than 300 pages.